===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 5.2.0-rc6-next-20190626 #23 Not tainted ----------------------------------------------------- syz-executor.5/22646 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: 00000000cae5fbe1 (&ctx->fault_pending_wqh){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] 00000000cae5fbe1 (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_ctx_read fs/userfaultfd.c:1045 [inline] 00000000cae5fbe1 (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_read+0x54d/0x1940 fs/userfaultfd.c:1203 and this task is already holding: 000000001b4667ab (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:363 [inline] 000000001b4667ab (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read fs/userfaultfd.c:1041 [inline] 000000001b4667ab (&ctx->fd_wqh){....}, at: userfaultfd_read+0x27a/0x1940 fs/userfaultfd.c:1203 which would create a new lock dependency: (&ctx->fd_wqh){....} -> (&ctx->fault_pending_wqh){+.+.} but this new dependency connects a SOFTIRQ-irq-safe lock: (&(&ctx->ctx_lock)->rlock){..-.} ... which became SOFTIRQ-irq-safe at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:167 spin_lock_irq include/linux/spinlock.h:363 [inline] free_ioctx_users+0x2d/0x490 fs/aio.c:620 percpu_ref_put_many include/linux/percpu-refcount.h:293 [inline] percpu_ref_put include/linux/percpu-refcount.h:309 [inline] percpu_ref_call_confirm_rcu lib/percpu-refcount.c:130 [inline] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 lib/percpu-refcount.c:165 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2114 [inline] rcu_core+0x67f/0x1580 kernel/rcu/tree.c:2314 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2323 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:535 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 __sanitizer_cov_trace_pc+0x0/0x50 rmap_walk+0x156/0x1c0 mm/rmap.c:1903 page_referenced+0x457/0x5e0 mm/rmap.c:874 page_check_references mm/vmscan.c:1033 [inline] shrink_page_list+0x1e94/0x55e0 mm/vmscan.c:1266 shrink_inactive_list+0x4ee/0xe30 mm/vmscan.c:1992 shrink_list mm/vmscan.c:2227 [inline] shrink_node_memcg+0x6d2/0x1600 mm/vmscan.c:2542 shrink_node+0x287/0x16f0 mm/vmscan.c:2762 shrink_zones mm/vmscan.c:2994 [inline] do_try_to_free_pages+0x3cb/0x11e0 mm/vmscan.c:3052 try_to_free_mem_cgroup_pages+0x320/0xbf0 mm/vmscan.c:3359 reclaim_high.constprop.0+0x12f/0x1a0 mm/memcontrol.c:2305 mem_cgroup_handle_over_high+0x8e/0x130 mm/memcontrol.c:2330 tracehook_notify_resume include/linux/tracehook.h:197 [inline] exit_to_usermode_loop+0x1fb/0x2d0 arch/x86/entry/common.c:168 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe to a SOFTIRQ-irq-unsafe lock: (&ctx->fault_pending_wqh){+.+.} ... which became SOFTIRQ-irq-unsafe at: ... lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x280/0x2d0 arch/x86/entry/common.c:168 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: &(&ctx->ctx_lock)->rlock --> &ctx->fd_wqh --> &ctx->fault_pending_wqh Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ctx->fault_pending_wqh); local_irq_disable(); lock(&(&ctx->ctx_lock)->rlock); lock(&ctx->fd_wqh); lock(&(&ctx->ctx_lock)->rlock); *** DEADLOCK *** 1 lock held by syz-executor.5/22646: #0: 000000001b4667ab (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:363 [inline] #0: 000000001b4667ab (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read fs/userfaultfd.c:1041 [inline] #0: 000000001b4667ab (&ctx->fd_wqh){....}, at: userfaultfd_read+0x27a/0x1940 fs/userfaultfd.c:1203 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: -> (&(&ctx->ctx_lock)->rlock){..-.} { IN-SOFTIRQ-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:167 spin_lock_irq include/linux/spinlock.h:363 [inline] free_ioctx_users+0x2d/0x490 fs/aio.c:620 percpu_ref_put_many include/linux/percpu-refcount.h:293 [inline] percpu_ref_put include/linux/percpu-refcount.h:309 [inline] percpu_ref_call_confirm_rcu lib/percpu-refcount.c:130 [inline] percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 lib/percpu-refcount.c:165 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2114 [inline] rcu_core+0x67f/0x1580 kernel/rcu/tree.c:2314 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2323 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:535 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1068 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 __sanitizer_cov_trace_pc+0x0/0x50 rmap_walk+0x156/0x1c0 mm/rmap.c:1903 page_referenced+0x457/0x5e0 mm/rmap.c:874 page_check_references mm/vmscan.c:1033 [inline] shrink_page_list+0x1e94/0x55e0 mm/vmscan.c:1266 shrink_inactive_list+0x4ee/0xe30 mm/vmscan.c:1992 shrink_list mm/vmscan.c:2227 [inline] shrink_node_memcg+0x6d2/0x1600 mm/vmscan.c:2542 shrink_node+0x287/0x16f0 mm/vmscan.c:2762 shrink_zones mm/vmscan.c:2994 [inline] do_try_to_free_pages+0x3cb/0x11e0 mm/vmscan.c:3052 try_to_free_mem_cgroup_pages+0x320/0xbf0 mm/vmscan.c:3359 reclaim_high.constprop.0+0x12f/0x1a0 mm/memcontrol.c:2305 mem_cgroup_handle_over_high+0x8e/0x130 mm/memcontrol.c:2330 tracehook_notify_resume include/linux/tracehook.h:197 [inline] exit_to_usermode_loop+0x1fb/0x2d0 arch/x86/entry/common.c:168 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:167 spin_lock_irq include/linux/spinlock.h:363 [inline] aio_poll fs/aio.c:1747 [inline] __io_submit_one fs/aio.c:1823 [inline] io_submit_one+0xeb5/0x2ef0 fs/aio.c:1860 __do_sys_io_submit fs/aio.c:1919 [inline] __se_sys_io_submit fs/aio.c:1889 [inline] __x64_sys_io_submit+0x1bd/0x570 fs/aio.c:1889 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.53807+0x0/0x40 ... acquired at: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] aio_poll fs/aio.c:1749 [inline] __io_submit_one fs/aio.c:1823 [inline] io_submit_one+0xefa/0x2ef0 fs/aio.c:1860 __do_sys_io_submit fs/aio.c:1919 [inline] __se_sys_io_submit fs/aio.c:1889 [inline] __x64_sys_io_submit+0x1bd/0x570 fs/aio.c:1889 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> (&ctx->fd_wqh){....} { INITIAL USE at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159 add_wait_queue+0x4c/0x170 kernel/sched/wait.c:23 aio_poll_queue_proc+0x9e/0x110 fs/aio.c:1712 poll_wait include/linux/poll.h:51 [inline] userfaultfd_poll+0x91/0x210 fs/userfaultfd.c:970 vfs_poll include/linux/poll.h:90 [inline] aio_poll fs/aio.c:1746 [inline] __io_submit_one fs/aio.c:1823 [inline] io_submit_one+0xe53/0x2ef0 fs/aio.c:1860 __do_sys_io_submit fs/aio.c:1919 [inline] __se_sys_io_submit fs/aio.c:1889 [inline] __x64_sys_io_submit+0x1bd/0x570 fs/aio.c:1889 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.46527+0x0/0x40 ... acquired at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_ctx_read fs/userfaultfd.c:1045 [inline] userfaultfd_read+0x54d/0x1940 fs/userfaultfd.c:1203 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x4a4/0x660 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:997 do_readv+0x15b/0x330 fs/read_write.c:1034 __do_sys_readv fs/read_write.c:1125 [inline] __se_sys_readv fs/read_write.c:1122 [inline] __x64_sys_readv+0x75/0xb0 fs/read_write.c:1122 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe the dependencies between the lock to be acquired and SOFTIRQ-irq-unsafe lock: -> (&ctx->fault_pending_wqh){+.+.} { HARDIRQ-ON-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x280/0x2d0 arch/x86/entry/common.c:168 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe SOFTIRQ-ON-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x280/0x2d0 arch/x86/entry/common.c:168 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x280/0x2d0 arch/x86/entry/common.c:168 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [] __key.46524+0x0/0x40 ... acquired at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_ctx_read fs/userfaultfd.c:1045 [inline] userfaultfd_read+0x54d/0x1940 fs/userfaultfd.c:1203 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x4a4/0x660 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:997 do_readv+0x15b/0x330 fs/read_write.c:1034 __do_sys_readv fs/read_write.c:1125 [inline] __se_sys_readv fs/read_write.c:1122 [inline] __x64_sys_readv+0x75/0xb0 fs/read_write.c:1122 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe stack backtrace: CPU: 1 PID: 22646 Comm: syz-executor.5 Not tainted 5.2.0-rc6-next-20190626 #23 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_bad_irq_dependency kernel/locking/lockdep.c:2025 [inline] check_irq_usage.cold+0x5b4/0x72e kernel/locking/lockdep.c:2223 check_prev_add kernel/locking/lockdep.c:2409 [inline] check_prevs_add kernel/locking/lockdep.c:2507 [inline] validate_chain kernel/locking/lockdep.c:2897 [inline] __lock_acquire+0x25bd/0x4c20 kernel/locking/lockdep.c:3880 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] userfaultfd_ctx_read fs/userfaultfd.c:1045 [inline] userfaultfd_read+0x54d/0x1940 fs/userfaultfd.c:1203 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x4a4/0x660 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:997 do_readv+0x15b/0x330 fs/read_write.c:1034 __do_sys_readv fs/read_write.c:1125 [inline] __se_sys_readv fs/read_write.c:1122 [inline] __x64_sys_readv+0x75/0xb0 fs/read_write.c:1122 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459519 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f135aedbc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000013 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459519 RDX: 0000000000000001 RSI: 0000000020001640 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f135aedc6d4 R13: 00000000004c664d R14: 00000000004db780 R15: 00000000ffffffff